Two lower courts in California both agreed that the search was legal and the California Supreme Court also agreed, saying that it all came down to whether the phone was on the suspect's person at the time of the arrest.

The court leaned on a 1976 U.S. Supreme Court decision that said you don't need a warrant to search a pack of cigarettes if they're on a person. But if you want to search a suitcase, you do need a warrant. A cell phone, the California court said, is more like a pack of smokes than it is like a suitcase.

In this show, we also talk to Jeffrey Rosen of George Washington University's law school. He says that similar cases around the country have broken both ways, some courts say such searches are legal, some say they aren't. But the issue really gets down to an unwillingness on the part of courts in general to define what electronic data is and what it isn't. And as more and more of our electronic information is stored not on our devices but on a cloud, seen through our devices, the issue is likely to get thornier.